A 4-month-old boy is brought to the office by his mother due to noisy breathing. Approximately a month ago, his mother first noticed a squeaky noise when he was crying or lying in his crib. The noise has become progressively louder and persistent. The patient was recently placed in a day care after his mother returned to work; she attributed the noisy breathing to a viral infection, but it has failed to resolve. He is breastfed but is fed formula at day care. The mother reports no episodes of difficulty breathing or bluish discoloration during feeding, but he often spits up a small amount after feeds. The patient was born at full term without complications and is up to date with vaccinations. He is afebrile; height and weight are at the 60th percentile. On physical examination, the patient appears well and smiles at the examiner. When the patient is placed supine on the examination table, inspiratory stridor is heard, which resolves quickly when he is placed in the prone position. No cyanosis is noted. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?

Question

A 4-month-old boy is brought to the office by his mother due to noisy breathing.  Approximately a month ago, his mother first noticed a squeaky noise when he was crying or lying in his crib.  The noise has become progressively louder and persistent.  The patient was recently placed in a day care after his mother returned to work; she attributed the noisy breathing to a viral infection, but it has failed to resolve.  He is breastfed but is fed formula at day care.  The mother reports no episodes of difficulty breathing or bluish discoloration during feeding, but he often spits up a small amount after feeds.  The patient was born at full term without complications and is up to date with vaccinations.  He is afebrile; height and weight are at the 60th percentile.  On physical examination, the patient appears well and smiles at the examiner.  When the patient is placed supine on the examination table, inspiratory stridor is heard, which resolves quickly when he is placed in the prone position.  No cyanosis is noted.  The remainder of the examination shows no abnormalities.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec25c8_d655_15b2_bc81_bbe73a128bc0_MD0003_00 This infant who has inspiratory stridor that worsens on supine positioning and who is otherwise feeding and growing well likely has laryngomalacia. Laryngomalacia is the most common cause of stridor in infants. Although the precise etiology is not known, the supraglottic tissues appear floppy and collapse on inspiration to partially block the airway. Crying and feeding worsen the stridor due to increased airflow. Prone positioning improves the stridor because the tongue moves anteriorly, partially relieving the obstruction. Stridor from laryngomalacia begins in the neonatal period and is loudest at age 4-8 months. The diagnosis is confirmed by visualizing the dynamic collapse of the supraglottic tissues using flexible laryngoscopy. Most patients also have concurrent gastroesophageal reflux (GER) (eg, spitting up of foods), and antireflux treatment often improves breathing (for reasons that are not entirely clear). Laryngomalacia usually resolves spontaneously by age 18 months. However, if it is associated with feeding difficulties, cyanosis, or failure to thrive, referral for surgical consultation is appropriate. (Choice A) A foreign body in the larynx or trachea could cause stridor but would likely also present with life-threatening acute respiratory distress. A foreign body in the lower airways would not characteristically present with stridor but could present with recurrent pneumonias that do not resolve radiographically. (Choice B) Allergic rhinitis typically presents with sneezing, rhinorrhea, nasal obstruction, and nasal itching. This patient has no nasal symptoms. (Choice C) Bilateral choanal atresia, or congenital blockage of the posterior nasal aperture, presents shortly after birth with cyclic cyanosis that worsens when newborns cannot breathe through the mouth (eg, during feeding) and improves when they do (eg, while crying). Unilateral choanal atresia commonly presents during childhood as persistent, unilateral nasal obstruction and discharge. (Choice D) Cow's milk allergy (eg, caused by the introduction of cow's milk protein-based formula) can present with a diverse array of IgE-mediated and non-IgE-mediated reactions, including eczema, vomiting, bloody stools, and failure to thrive. Respiratory symptoms would be rare, particularly in isolation. (Choice F) Laryngotracheobronchitis (croup) presents with stridor and shortness of breath. However, viral croup, often caused by parainfluenza virus, presents with infectious symptoms (eg, fever, coryza, barking cough) and resolves within a week. Educational objective: Laryngomalacia is the most common cause of stridor in infants and is due to collapse of the supraglottic tissues during inspiration. Stridor increases with exertion (eg, crying, feeding) and improves with prone positioning. References: Laryngomalacia: is there an evidence base for management? (http://www.ncbi.nlm.nih.gov/pubmed/29067893) Laryngomalacia. (http://www.ncbi.nlm.nih.gov/pubmed/27301595) A systematic review of laryngomalacia and acid reflux. (http://www.ncbi.nlm.nih.gov/pubmed/22745201)

A 4-Month-Old Boy Is Brought to the Office by His